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arXiv · 2503.23075

Boosting classical and quantum nonlinear processes in ultrathin van der Waals materials

Xiaodan Lyu·Leevi Kallioniemi·Hongbing Cai·Liheng An·Ruihuan Duan·Shuin Jian Wu·Qinghai Tan·Chusheng Zhang·Ruihua He·Yansong Miao·Zheng Liu·Alexander Ling·Jesus Zúñiga Perez·Weibo Gao
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Abstract

Understanding and controlling nonlinear processes is crucial for engineering light-matter interaction and generating non-classical light. A significant challenge in ultra-thin nonlinear materials is the marked diminution of the nonlinear conversion efficiency due to the reduced light-matter interaction length and, in many cases, the centrosymmetric crystalline structures. Here we relax these limitations and report a giant boost of classical and quantum nonlinear processes in ultrathin van der Waals materials. Specifically, with a metal-nonlinear material heterostructure we enhance classical second-harmonic generation in h-BN flakes by two-orders of magnitude. Moreover, we have engineered a metal-SiO2-nonlinear material heterostructure resulting in a remarkable two orders of magnitude augmentation of the quantum spontaneous parametric down-conversion (SPDC) in NbOCl2 flakes. Notably, we demonstrate SPDC in a 16 nm-thick NbOCl2 flake integrated into the proposed structure. These findings simplify on-chip quantum state engineering and accelerate the use of van der Waals materials in nonlinear optoelectronics.

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Xiaodan Lyu, Leevi Kallioniemi, Hongbing Cai, Liheng An, Ruihuan Duan, Shuin Jian Wu, Qinghai Tan, Chusheng Zhang, Ruihua He, Yansong Miao, Zheng Liu, Alexander Ling, Jesus Zúñiga Perez, Weibo Gao. 2025-03-29. Boosting classical and quantum nonlinear processes in ultrathin van der Waals materials. https://arxiv.org/abs/2503.23075

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